In December 2004, the 3GPP (3rd Generation Partnership Project, 3rd generation partnership project) started an all-IP packet domain core network evolution project (System Architecture Evolution, SAE), and now the project is renamed EPS (Evolved Packet System, evolved packet system). The EPS aims at “establishing a transplantable 3GPP system architecture with the characteristics of high data rate, short delay, data packetization, and supporting various types of wireless access technologies”. The EPS system is classified into an E-UTRAN (Evolved Universal Terrestrial Radio Access Network, evolved universal terrestrial radio access network) and an EPC (Evolved Packet Core, evolved packet core).
FIG. 1 is a schematic diagram of an EPS system architecture in the prior art.
The E-UTRAN includes an eNB (E-UTRAN NodeB, E-UTRAN NodeB), which is mainly responsible for receiving and transmitting wireless signals and communicates with a terminal through an air interface.
The EPC includes an HSS (Home Subscriber Server, home subscriber server), an MME (Mobility Management Entity, mobility management entity), an S-GW (Serving Gateway, serving gateway), and a P-GW (Packet Data Networks Gateway, packet data networks gateway).
The HSS is a location for permanently storing subscriber subscription data, and is located in the home network to which a subscriber subscribes.
The MME is a location for storing subscriber subscription data in the current network and is responsible for NAS (Non-Access Stratum, non-access stratum) signaling management from a terminal to a network, and for achieving tracing and paging management functions when a UE is in an idle state.
The S-GW is a gateway from a core network to a wireless system and is responsible for the user plane bearer from a terminal to a core network, data buffering when a terminal is in an idle state, initiating a service request on the network side, lawful interception, and packet data routing and forwarding.
The P-GW is a gateway between the EPS and an external network of the system and is responsible for terminal functions such as IP address allocation, charging, packet filtration, and policy application.
As shown in FIG. 2, in the foregoing EPS architecture, when a UE requires a new P-GW for service transmission, a new PDN connection needs to be initiated, and the procedure is as follows:
Before the establishment of a new PDN in the EPS architecture, the following describes technical terms used in the procedure beforehand.
PDN: Packet Data Networks, packet data networks;
APN: Access Point Name, access point name;
initial attach: initial attach;
Bearer ID: bearer ID;
EPS Bearer: EPS bearer;
PCC: Policy and charging control, policy and charging control;
IP-CAN: IP-connectivity access network, IP-connectivity access network;
PCRF: Policy and Charging Rules Function, policy and charging rules function;
dedicated bearer: dedicated bearer;
PCEF: Policy and Charging Enforcement Function, policy and charging enforcement function;
QoS: Quality of Service (quality of service);
CGI: Cell Global Identification, cell global identification;
RAI: Routing Area Identity, routing area identity;
SAI: Serving Area Identity, serving area identity;
APN Restriction: APN restriction;
TEID: Tunnel Endpoint Identifier, tunnel endpoint identifier; and
RRC: Radio Resource Control, radio resource control.
The procedure for establishing a PDN connection in the EPS architecture is as follows:
1. A UE sends a PDN connectivity request (PDN Connectivity Request) message, where the message carries an APN, and an MME identifies whether the APN provided by the UE is allowed for use according to its stored subscriber subscription information.
2. If the Request Type of the PDN Connectivity Request message is “handover (handover)”, the MME uses a P-GW in the stored subscriber subscription information to establish a PDN connection, and if the Request Type is “initial attach (initial attach)”, the MME selects a P-GW according to a standard P-GW selection principle, allocates a Bearer ID to the UE, and sends a create session request message to the S-GW, where the create session request carries a P-GW address selected by the MME.
3. The S-GW establishes a new entry in its stored EPS Bearer list and at the same time sends a create session request (Create Session Request) message to the P-GW, where the P-GW is the P-GW corresponding to the P-GW address carried in the create session request message sent by the MME, which is described in step 2. Then the S-GW buffers a downlink packet from the P-GW until a data channel to an eNodeB is established.
4. If the Request Type of the PDN connectivity request is not “handover (handover)” and a dynamic PCC is deployed on the P-GW, the P-GW initiates an IP-CAN Session Establishment procedure to obtain default PCC rules through communication with a PCRF entity, which may lead to the establishment of a plurality of dedicated bearers. If the P-GW is configured to activate predefined PCC rules for a default beater, the P-GW does not need to communicate and interact with the PCRF. If a Handover instruction exists, the P-GW initiates a PCEF-Initiated IP-CAN Session Modification procedure. If no dynamic PCC is deployed on the P-GW, the P-GW activates a local QoS policy.
5. The P-GW establishes a new list entry in its EPS Bearer list and generates a Charging ID. The new list entry allows the P-GW to directly perform data forwarding in the PDN and the S-GW and start charging. The P-GW returns a create session response (Create Session Response) message to the S-GW, and the P-GW allocates an address to the UE. If the P-GW selects a different PDN Type for the UE, the P-GW needs to send a specific change cause value (network preference, single address bearers only) to the UE. For a request provided with a Handover instruction, the P-GW needs to allocate an IP address that is the same as that in non-3GPP access to the UE.
6. For an established bearer, if a CGI/SAI/RAI needs to be reported to the P-GW, the S-GW stores the reporting request and reports to the P-GW when the information changes, and the S-GW returns a create session response (Create Session Response) message to the MME.
7. If the MME receives an APN Restriction parameter, the MME stores the information and check whether a conflict exists according to Maximum APN Restriction. If the PDN Connectivity Request (PDN Connectivity Request) message is accepted, the MME sends a PDN Connectivity Accept (PDN Connectivity Accept) message to the eNodeB. The information is contained in a bearer setup request (Bearer Setup Request) message of an S1_MME control message. The S1_MME control message includes the address TEID of the user plane on the S-GW side.
8. The eNodeB sends an RRC connection reconfiguration (RRC Connection Reconfiguration) message to the UE, and the RRC connection reconfiguration message includes a PDN Connectivity Accept message.
9. The UE sends an RRC connection reconfiguration complete (RRC Connection Reconfiguration Complete) message to the eNodeB;
10. The eNodeB sends an S1-AP bearer setup response (Bearer Setup Response) message to the MME, where the message includes the address and TEID of the eNodeB used for establishing an S1-U.
11. The UE sends a Direct Transfer (direct transfer) message to the eNodeB to indicate that the PDN connection is established.
12. The eNodeB sends an Uplink NAS Transport (PDN Connectivity Complete) (uplink NAS transport PDN connectivity complete) message to the MME. When the UE receives the PDN connectivity accept (PDN Connectivity Accept) message and obtains a PDN address, the UE may send an uplink data packet. If the UE requires an address of IPv4v6 type but only obtains an address of IPv6 or IPv4 type, and the cause value is “single address bearers only”, the UE may establish another PDN connection to the same APN and requires a single IP address, and the type of the required IP address is different from that of the obtained IP address. If the UE requires an IPv4v6 address but only obtains an IPv6 address prefix and an interface identifier, and no cause value is obtained, the UE may consider that the request for the address of a Dual Address PDN is successful.
13. After receiving the bearer setup response (Bearer Setup Response) and PDN connectivity complete (PDN Connectivity Complete) messages, the MME sends a modify bearer request (Modify Bearer Request) message to the S-GW.
13a: If the bearer setup response (Bearer Setup Response) and PDN connectivity complete (PDN Connectivity Complete) messages in step 13 contain a Handover instruction, the S-GW sends a modify bearer request (Modify Bearer Request) message to the P-GW, and the P-GW sends subsequent downlink packets to the S-GW.
13b: The P-GW sends a modify bearer response (Modify Bearer Response) message to the S-GW.
14: The S-GW sends the modify bearer response (Modify Bearer Response) to the MME, and the S-GW starts sending buffered downlink data packets.
15. After the MME receives the modify bearer response (Modify Bearer Response) message, if the Request Type is not “handover”, the UE is allowed to be handed over to a non-3GPP network, and the UE selects a new PDN-GW when it is the first time the UE establishes a connection to a certain PDN (APN), the MME needs to update the address of the PDN-GW to an HSS.
16. The HSS stores a PDN-GW identity and a related APN and sends a notify response (Notify Response) to the MME.
The foregoing describes the process of establishing a new PDN in the EPS architecture.
With the technology development, the 3GPP proposes the concept of an H(e)NB (Home (e)NodeB, home base station) based on an NB (Node B, base station) and an eNB. The H(e)NB is mainly applied to family and enterprise environments to generally provide favorable charging or free services within the coverage of an H(e)N (Home Network, home network), for example, in an airport, a terminal may enjoy free network services, but the charge is higher if the terminal enters the coverage of a macro network in the moving process. The concept of CSG (Closed Subscriber Group, closed subscriber group) is proposed in the H(e)NB. The CSG marks a user group, and the user group is allowed to access a cell (CSG cell) which is restricted for access in one or more PLMNs (Public Land Mobile Network, public land mobile network). The CSG cell is a cell under a PLMN and broadcasts a specific CSG ID. Only members who belong to the CSG ID can access the cell, and all the CSG cells sharing the same ID work as an independent group, facilitating mobility management and charging.
The foregoing H(e)NB is mainly applied to family and enterprise environments. An LIPA service is included in the service demands of the H(e)NB. The LIPA service is defined as follows:
LIPA (Local IP Access, local IP access) refers to a UE with an IP capability accessing an entity with another IP capability in the same family/enterprise IP network in a wireless manner by using the H(e)NB. As shown in FIG. 3, the execution of service data in local IP access bypasses the core network of an operator.
FIG. 4 is a schematic diagram of a common architecture of a local home base station in the prior art.
In an L-GW (Local Gateway, local gateway) architecture, an UE establishes two PDN (Packet Data Networks, packet data networks) connections, where one PDN connection is used for core network services of an operator and the other PDN connection is used for LIPA services, and the LIPA PDN may have a specific APN (Access Point Name, access point name) identification. For establishing an independent PDN connection, an H(e)NB needs to be locally configured with a local gateway, and the local gateway may allocate an IP address to the UE for LIPA services to use. This architecture enables the UE which supports a plurality of PDN connections to use LIPA and the core network of a mobile operator at the same time. Therefore, the UE has a plurality of IP addresses. Mobility management signaling between the UE and the network, as well as UE authorization, authentication and registration performed before the establishment of the PDN connection for LIPA, is implemented in the core network of the mobile operator.
In a local home base station network (Local H(e)NB Network, LHN) shown in FIG. 4, a series of home base stations are defined, and meanwhile, these home (base stations establish IP connections to one or more L-GWs. These L-GWs may perform LIPA by using local PDN(s). Meanwhile, one H(e)NB only belongs to one independent local home base station network, one L-GW only belongs to one independent LHN, and one L-GW is capable of accessing one or more PDNs and is capable of accessing one PDN by using a plurality of LHNs. The local home base station network may also be referred to as a local network. Meanwhile, the local network may have a local network identity (LHN ID) or a local network name (LHN Name).
In the specific implementation process, the LHN has two novel network architectures. FIG. 5 shows a novel network architecture 1 of the local home base station, which includes network elements such as an L-GW, an HeNB, a UE, an SGW, and an MME, where the L-GW is a novel independent logical entity in the local network, and is connected to the S-GW through an S5 interface and at the same time connected to the home base station (Home eNodeB or Home NodeB) through a novel Sxx interface; the UE is connected to the HeNB through an interface Uu; the HeNB and the MME are connected through an interface S1-MME; and the SGW and the MME are connected through an S11. Optionally, the architecture also includes network elements of an SeGW and an HeNB GW, where the HeNB GW is connected to the SGW through an S1-U interface, and is connected to the MME through an S1 interface.
A novel architecture 2 of the local home base station network is as shown in FIG. 6, and the network architecture includes network elements such as an L-GW, an MME, an HeNB, a UE, an S-GW, and a P-GW. The L-GW serves as a novel independent logical entity in the local network, and is connected to the MME through an S11 interface and connected to the home base station through an Sxx interface. The address of the L-GW has two meanings: one is an L-GW core network address (L-GW CN Address), used for communicating with the core network, and the other is an L-GW local network address or an L-GW local address (L-GW LN Address), used for communicating with the home base station. Meanwhile, the HeNB also has two addresses: one is an HeNB core network address (HeNB CN Address), used for communicating with the core network, and the other is an HeNB local network address or an HeNB local address (HeNB LN Address), used for communicating with the L-GW through establishing a direct tunnel. The MME and the S-GW are connected through an S1-MME interface, and the S-GW and the P-GW are connected through an S5/8; and the UE and the HeNB are connected through a Uu interface, and the MME and the HeNB are connected through an S1-MME. Optionally, the architecture also includes network elements of an SeGW and an HeNBGW, where the HeNBGW is connected to the SGW through an S1-U interface, and is connected to the MME through an S1 interface.
During the implementation of the present invention, the inventors find that the prior art has at least the following problem:
In the architectures 1 and 2 of the local home base station network, the procedure for establishing a PDN connection in the prior art is inapplicable to the architectures 1 and 2, and is incapable of establishing local IP access and tunnel connection between the H(e)NB and the L-GW for the UE.